The present invention relates to a vehicle transmission with an automatic clutch, and more particularly to means for controlling reengagement of a clutch.
A vehicle transmission with an automatic clutch is known in which for gear shifting a clutch is disengaged with the assistance of a vacuum of a source of vacuum, via a control valve having a solenoid actuated clutch release valve and a clutch servo. The solenoid actuated clutch release valve connects the clutch servo to the source of vacuum when a solenoid thereof is energized to disengage the clutch. A current is supplied to the solenoid when a shift switch and an acceleration switch are closed, the shift switch being closed only when a gear shift lever of a gear box is manipulated to shift gears, the acceleration switch being closed only when an engine accelerator is released. The reengagement of the clutch commences upon opening of the accelerator switch when the accelerator is depressed and/or upon opening of the shift switch when the gear shift lever is released.
Because, in this control arrangement, the reengagement of the clutch commences as soon as a driver depresses the accelerator, despite that the he still manipulates the gear shift lever, there is a drawback that when the vehicle is at a standstill, if a driver happens to depress the accelerator to open the acceleration switch before the gear is not yet completely engaged and when the shift switch remains closed, the reengagement of the clutch is carried out to connect an engine crankshaft to a gear box drive shaft so that the gears are very noisily ground together as soon as the gear shift lever is moved further to a position to complete gear engagement in the gear box and in some cases the gear engagement is hampered.
Another drawback is that when the vehicle is at a standstill, if the driver does not wish to move the vehicle from its present stationary position and thus still holds the gear shift lever to keep the shift switch closed, accidential depressing of the accelerator will cause the vehicle to move off regardless of the driver's intention.